This invention relates to improved synthetic asphalt recycled tire rubber emulsions and to processes for making these improved emulsions. These improved emulsions are mixtures of ingredients comprising gilsonite, man-made asphaltene residiums, tall oil products including crude tall oil, tall oil, and tall oil pitch, which may be modified with petroleum asphalt, petroleum base oils, petroleum base lube oil extracts, reclaimed and recycled motor oil, reclaimed and recycled motor oil fluxes, water, surfactants, clays and clay-like materials, chemicals, mineral fillers, crushed and sieve sized mineral aggregates, polymers, natural and man-made fibers, and granulated minus 10 mesh to minus 80 mesh recycled tire rubber. The inventor herein has had in effect U.S. Pat. No. 4,437,896 issued Mar. 20, 1984, (the '896 patent). In this referenced patent are formulations and processes for making various synthetic asphalt compositions including synthetic asphalt emulsions. The present invention comprises improvements to synthetic asphalt recycled tire rubber emulsions and processes for making them. These improvements include exact formulations and processes not disclosed in, taught in, or apparent from the '896 patent, all of which have been developed after the '896 patent was granted in 1984.
Petroleum asphalt is typically made from refining crude petroleum oil. Petroleum asphalt is comprised of four major hydrocarbon components: (1) asphaltenes, (2) polar resins, (3) aromatic oils, and (4) saturated oils. The asphaltenes and polar resins are generally dispersed in the aromatic and saturated oils. Two primary factors that determine the grade of the asphalt are the proportion of the asphaltenes and polar resins together, to the proportion of the aromatic and oils, and the viscosity of the resulting mixture. The physical characteristics of petroleum asphalt such as needle penetration, flash point, kinematic viscosity, absolute viscosity, specific gravity, rotational viscosity, complex modulus as determined by dynamic shear rheometers, and aging indexes all emerge from the dispersion of asphaltenes and polar resins in the aromatic and saturated oils present within the petroleum asphalt.
Synthetic asphalts as in the '896 patent, are mixtures of gilsonite, or man-made asphaltene residiums in a tall oil product. Gilsonite is a naturally occurring bituminous hydro-carbon mineral found and mined in Northeastern Utah. Gilsonite is typically comprised of 70 to 90 percent by weight asphaltenes, 5 to 20 percent by weight polar resins, and 5 to 10 percent by weight aromatic and saturated oils. Gilsonite has a melting, or softening point of 140.6° C. (285° F.) to 162.8° C. (325° F.). Man-made asphaltene residiums are very similar in chemical composition and melting, or softening point to gilsonite. Man-made asphaltene residiums are derived from solvent extraction processes for refining crude petroleum oil. In these processes, liquid propane, butane, and/or isobutane under heat and pressure are utilized to precipitate the asphaltenes and polar resins out of the crude petroleum oil. The aromatic and saturated oils may then be easily refined into gasoline, jet fuel, diesel fuel, and lube oils. The asphaltenes and polar resins precipitated out of the crude petroleum oil by these solvent extract refining processes are commonly known as asphaltene residiums.
Tall oil products, which include crude tall oil, tall oil, and tall oil pitch, are derived from the acid digestion of wood chips and saw dust to extract cellulose from which paper is made. During the acid digestion of wood particles and saw dust, the glue that holds the cellulose together is separated from the cellulose. The cellulose is collected, and the mixture of water, acid and glue from the wood particles and saw dust is further separated. One of these separated fractions, known as fatty acid heads, is dewatered, and then is known as crude tall oil. The crude tall oil is then refined in a similar manner as crude petroleum oil, and from this refining processes obtained turpentine, tall oil, rosin, and tall oil pitch. Tall oils are mixtures of oleic and linoleic acids, and are unsaturated oils. Tall oil pitch is a complex mixture of high molecular weight oily and resinous hydrocarbons that are polar. Crude tall oil, tall oil, and tall oil pitch may be used to make synthetic asphalt mixtures by combining them with gilsonite or man-made asphaltene residiums in various proportins at temperatures of 140.6° C. (285° F.) to 260° C. (500° F.). These synthetic asphalts may be made to conform to many of the physical properties and specifications of petroleum asphalts through careful selection of the tall oil product, or blends of tall oil products, with the gilsonite or man-made asphaltene residium as taught in the '896 patent.
Synthetic asphalt may be further modified by the addition of petroleum asphalt, petroleum base oils, petroleum base lube oil extracts, reclaimed and recycled motor oils, reclaimed and recycled motor oil fluxes, polymers, and recycled and granulated minus 10 mesh to minus 80 mesh tire rubber. Polymers that may be used to modify the synthetic asphalt are any polymer compatible with petroleum asphalt such as styrene butadiene styrene coblock polymers, styrene isoprene styrene coblock polymers, styrene butadiene polymers, styrene ethylene styrene butadiene polymers, ethylene vinyl acetate polymers added as a dry powder or in latex form, neoprene latex polymer, acrylic and vinyl acrylic latex polymers, styrene butadiene latex polymer, and other polymer latexes. Synthetic asphalt may also be further modified by the addition of recycled and granulated minus 10 mesh to minus 80 mesh tire rubber. Other modifiers for synthetic asphalt include mineral fillers, crushed and sieve sized mineral aggregates, clays and clay-like materials, and natural or man-made fibers, which when added form mastic synthetic asphalt mixtures.
The cost of petroleum asphalt emulsions, and petroleum base asphalt recycling and maintenance emulsion products has risen sharply in recent years. The availability of emulsions made from synthetic asphalt mixtures may help keep down the costs of road repair, maintenance, and reconstruction in the future. Emulsions of synthetic asphalt mixtures that include minus 10 mesh to minus 80 mesh granulated recycled tire rubber are particularly useful for the construction, repair, and maintenance of city streets, county roads, and state highways. There are incentives in many states to encourage the use of emulsions containing recycled tire rubber for road repair and reconstruction. Preparing such emulsions though is very difficult. This invention sets forth new and unique successful formulations and processing techniques to prepare recycled tire rubber emulsions.
All of the product and material names in the above descriptions, as well as the processes from which they are derived are well known to chemists and technicians within the petroleum refining industry, asphalt products industry, and paper making industry. These chemists and technicians will be able to clearly understand and make the improved synthetic, and improved modified synthetic asphalt tire rubber emulsions from the formulations and processes disclosed herein.